AcrySof ReSTOR Multifocal versus AcrySof SA6AT Monofocal Intraocular Lenses: A Comparison of Visual Acuity and Contrast Sensitivity Hassan Hashemi, MD,2 Hamid Reza Nikbin, MD 2 Mehdi Khabazkhoob, MSc 2 Abstract Purpose: To compare visual quality in patients receiving Alcon AcrySof ReSTOR versus AcrySof SA6AT intraocular lenses (IOL) Methods: In this interventional study, patients with senile cataract undergoing surgery were enrolled. The age of the patients ranged between 4 and 85 years, and their potential preoperative vision was 2 / 3 or better. In all patients phacoemulsification was performed through a temporal 2.8 mm incision. Postoperative visual acuity (VA), refraction, and contrast sensitivity (with and without glare) tests were done at and 3 months. A total of eyes were evaluated. A IOL was implanted in 52.5% of cases, and in the rest, a IOL was used. Results: At 3 months, the mean distant VA without and with correction was. and.4 logmar, respectively, in the IOL group, and.4 and.3 logmar, respectively, in the IOL group (P>.). The near VA without and with correction was.4 and.5 logmar, respectively, in the group and 2 and.4 logmar, respectively, in the IOL group, statistically significantly better in the group (P=.38). At 3 months after surgery, contrast sensitivity with and without glare showed statistically significant inter-group differences at 6, 2 and 8 cycles per degree (CPD), and at 6 and 2 CPD, respectively. These figures were higher in group. Conclusion: Use of IOLs in cataract surgery can restore near vision to some extent in addition to distant vision. Contrast sensitivity in recipients of IOLs is lower than those with IOLs. Keywords: Multifocal Lenses, Monofocal Lenses, Distant Visual Acuity, Visual Acuity Iranian Journal of Ophthalmology 29;2(4):25-3 29 by the Iranian Society of Ophthalmology. Associate Professor of Ophthalmology, Eye Research Center, abi Eye Hospital, Tehran University of Medical Sciences 2. Noor Ophthalmology Research Center, Noor Eye Hospital Received: July 5, 29 Accepted: October 2, 29 Correspondence to: Hassan Hashemi, MD Eye Research Center, abi Eye Hospital, Tehran, Iran, Tel: +98 2 554494-6, Email: hhashemi@noorvision.com Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran, Tel: +98 2 886555 29 by the Iranian Society of Ophthalmology Published by Otagh-e-Chap Inc. 25
Iranian Journal of Ophthalmology Volume 2 Number 4 29 Introduction The technique of choice in senile cataract is phacoemulsification with intraocular lens (IOL) implantation to correct refractive errors. IOLs used in cataract surgery are either or ; the former group can only correct distant vision and fail to solve patients problems with near vision which are due to impaired accommodation. As a solution, two types of IOLs were designed for correcting both near and distant vision in patients undergoing cataract surgery, as well as compensating for the impaired accommodation. These IOLs are further classified as accommodative and IOLs; the latter group comes in refractive and defractive subgroups. There is claim that IOLs are capable of correcting refractive errors as well as eliminating patients need for near vision addition.,2 There are reports indicating that IOLs are responsible for some degrees of halo, glare 3 and reduced contrast sensitivity. Nonetheless, patients seem to be very satisfied with these lenses. 4-6 In a study by Blaylock et al, 7 they found that lenses could be useful for correcting near vision in cases of presbyopia, and the quality of life in recipients of these lenses was significantly improved after surgery. In the current study, we present a comparison of AcrySof ReSTOR and AcrySof SA6AT IOLs in terms of near and distant visual acuity (VA) and contrast sensitivity after cataract surgery. Methods In this interventional study, we enrolled patients with senile cataract whose diagnosis had been made by an ophthalmologist. The inclusion criteria were an age between 45 and 85 years, a potential preoperative VA of 2 / 3 or better, and the availability of the IOL power in the market. Patients who had any systemic disease affecting vision or any other ocular conditions were excluded. The study protocol was explained to selected patients and upon their consent to participate further procedures were discussed with the patients so that they could choose the type of IOL. To eliminate the effect of confounding factors, all surgeries were done by a single skilled surgeon. Depending on the type of implanted IOL - the AcrySof SA6AT and the AcrySof ReSTOR - patients were fit into two 26 groups. In all cases, a similar phacoemulsification technique with a 2.8 mm temporal incision was performed. Preoperative examinations included ) Uncorrected distant visual acuity (UDVA) and corrected distant visual acuity (CDVA) tests using the standard Snellen chart; 2) manifest refraction; 3) slit-lamp examination; 4) fundoscopy; 5) measurement of intraocular pressure; 6) IOL power determination using the IOLMaster; and 7) keratometry and topography. Postoperative examinations, scheduled for and 3 months after surgery were distant VA, uncorrected near visual acuity (UNVA), corrected near visual acuity (CNVA), refraction tests, slit-lamp examination and contrast sensitivity tests with and without glare using the CSV-. In all cases, VA tests were done unilaterally and NVA was tested after CDVA tests. refraction was compared between the groups to show how much the lens could lower the patient s dependence on spectacle during reading or near work. This figure was measured by a retinoscope while the patients were focusing on a near target 4 cm away from their eyes. The amounts of add were calculated according to this measurement. The Research and Ethics Committee of Noor Vision Correction Center and the Ethics Committee of the National Research Center for Medical Sciences approved the study. All participants in this study were informed about the project and the procedures in their native language before being enrolled. The participants agreement for examination was obtained verbally. Analyses were done with the SPSS version.5 software. Analysis procedures including the independent sample test and repeated measures ANOVA were used. Results The study duration was from February 26 to October 27. During this period, eyes of 8 patients eligible for cataract surgery met the inclusion criteria and were enrolled in the study. In 2 patients, both eyes were operated on. The patients were male in 62% of cases, and their mean age was 62.9±.5 (range, 4 to 79) years. A IOL was implanted in 52.5% of cases and the rest received a IOL. There were no statistically
Hashemi et al AcrySof ReSTOR vs. AcrySof SA6AT significant differences in terms of age or gender between the two groups of patients. There was no loss of follow-up at month after surgery while 3 patients failed to have follow-up at 3 months after surgery. Visual acuity Table summarizes the results of VA tests in the logmar scale, one month and 3 months after surgery. As demonstrated in the table, the inter-group difference in UDVA and CDVA at and 3 months was not statistically significant. The UNVA was significantly better in the group at one and 3 months after surgery, but the CNVA was not statistically significantly different between the two groups. Table 2 summarizes percentages of eyes in different ranges of VA in the two groups of Table. Visual acuity in the logmar scale at one and three month follow-up visits Multifocal patients. We found that at 3 months after surgery, 6.% in the group and 59.5% in the group had / VA. Refraction The mean cylindrical error was -.9 D in the group and.86 D in the group at preoperative (P=65), and spherical errors showed no difference between the two groups, postoperatively (P=.389). Results of the refraction tests, one and 3 months after the operation are stated in detail in Table 3. The spherical error measured in near and distant refraction tests were not significantly different between the two groups at either follow-up visit; nor were the spherical equivalent refractions. Monofocal month 3 month month 3 month P-value Mean±SD Mean±SD Mean±SD Mean±SD month 3 month UCVA.4±..±. ±.4±.3 3 7 BCVA.4±.7.4±.7.2±.4.3±.3.5.96 UCVA ±.6.4±.6 6± 2±.6.35.38 BCVA.2±.6.5±.8 2±.6.4±.9.46.33 : Comparison and with independent T-test UCVA: Uncorrected visual acuity BCVA: Best corrected visual acuity Table 2. Percentages of cases in different visual acuity ranges UCVA BCVA Multifocal Monofocal Multifocal Monofocal 8/-/ 69.6 57. 87.. 5/-7/ 23.9 35.7 3.. <5/ 6.5 7... 8/-/ 43.6 4.5 87.2 94.6 5/-7/ 5.3 37.8 2.8. <5/ 5. 2.6. 5.4 UCVA: Uncorrected visual acuity BCVA: Best corrected visual acuity 27
Iranian Journal of Ophthalmology Volume 2 Number 4 29 Table 3. Results of refraction tests in the two groups of patients at one and three months after surgery Index Distance Time Multifocal Monofocal P-value Sphere month 3±. -.2±.63.56 3 month 3±.5 -.2±.72.72 month.7±.5 6±.5.72 3 month.59±.84.43±.8.492 Cylinder Spherical equivalent : Comparison and with independent T- test Contrast sensitivity The inter-group differences in contrast sensitivity, measured with and without glare at 3, 6, 2, and 8 cycles per degree (CPD), were statistically significant at one month after surgery at 2 and 8 CPD measured with.6.4.2.8.6.4 3cycle 6cycle 2cycle 8cycle Contrast Sensitivity with Glare in month month -.82±.88 -.7±.5.468 3 month -.68±.55 -.8±.5 6 month -.55±.92 -.6±.55.88 3 month -.53±.68 -.54±.56.94 month -.8±.24 -.37±.63.346 3 month -.±.55 -.32±.78.47 month.42±.5 -.4±.7.87 3 month.33±.97.6±.25.539 glare. At 2 CPD with glare, the contrast sensitivity in the and IOL groups at one month after surgery was.88 and.8, respectively (P=.) (Figure )..8.6.4.2.8.6.4 3cycle 6cycle 2cycle 8cycle Contrast Sensitivity with non Glare in month.8.6.4.2.8.6.4 3cycle 6cycle 2cycle 8cycle Contrast Sensitivity with Glare in 3month.8.6.4.2.8.6.4 3cycle 6cycle 2cycle 8cycle Contrast Sensitivity with non Glare in 3month 28 Figure. Contrast sensitivity in and lenses at and 3 months
Hashemi et al AcrySof ReSTOR vs. AcrySof SA6AT These figures were.45 and.62, respectively, at 8 CPD. At one month after surgery, mean contrast sensitivity without glare was better in the group at 6, 2, and 8 CPD (Figure ). At 3 months after surgery, the mean contrast sensitivity with glare at 6, 2, and 8 CPD and the mean contrast sensitivity without glare at 6 and 2 CPD were significantly better in the group. Other values were not statistically different between the two groups (Figure ). Discussion This study was designed and conducted to compare near and distant vision in two groups of patients receiving and IOLs during cataract surgery to supplement our knowledge regarding the role of these two types of lenses in the correction of distant vision. Considering the special features in the design of IOLs to restore near vision in patients, a number of questions are raised. For example, does relative correction of near vision with IOLs reduce their efficiency in restoring distant vision? Or, is improved near vision to the expense of decreased contrast sensitivity? The major weakness of this study was the selection bias created because of 2% to 3% loss of follow-up at 3 months after surgery. As demonstrated in the results section, mean UDVA was.4 logmar in the group and reached. logmar at 3 months. In the group, these figures were and.4 logmar, respectively; there were no significant differences between the two groups during the follow-up period. Ortiz et al 8 compared the visual performance of these two types of IOLs and reported a UDVA of 8 / in both groups, indicating no significant differences. Cillino et al 6 compared 4 types of refractive and defractive IOLs in cataract patients showing no significant difference in terms of uncorrected visual acuity (UCVA). Insignificant differences in UDVA between and IOLs have also been reported by Souza et al 9 as well as Chiam et al who studied 8 patients (4 in each group) and found that the decimal UDVA at 2 months was.79 and.85 decimal, respectively. Overall, reports on this issue agree that IOLs are capable of correcting DVA just as well as IOLs.,3, The CDVA, as demonstrated in table, was not significantly different between the two groups either;.3 and.4 logmar in the and groups, respectively. Similarly, there were no significant differences in the CDVA reported for and groups in the study by Chiam et al (.98 and.94 decimal, respectively) and Otriz et al 8 (.9 and. decimal, respectively) at six months. In another study by Chiam et al 2, again they found no significant differences between their two and groups in terms of percentage of cases achieving 2 / 2 CDVA (82% and 86%, respectively). Similarly, in our patients, the percentage of cases achieving 2 / 2 CDVA in the and groups were very close (59.9% and 6.%, respectively). Overall, these results indicate that there are no significant differences between and IOLS in terms of distant vision with or without correction. In patients whose only concern is restoring distant vision, the extra cost of IOLs may be unnecessary, and IOLs may be a more appropriate choice. The highlight of the present study was the differences we found between the two groups in UNVA. At 3 months after surgery, the UNVA in the and groups were 2 and.4, respectively, after correction of DVA, and the inter-group difference was statistically significant. Findings in other studies support our results, and they agree that or defractive IOLs improve UNVA. 9,2,3 Ortiz et al 8 reported a mean UNVA of.7 and.9 decimal in their and patients, respectively; statistically significantly better in the group. Cillino et al 6 stated that these figures were.6 and.72 decimal, respectively; the difference was statistically significant and they concluded that defractive IOLs are better capable of correcting UNVA. In the report by Chiam et al these figures were.34 and.72 decimal, respectively; again, the evidence on NVA was in favor of IOLs. Overall, since the IOLs are designed to improve near vision, the results were not unexpected. In terms of CNVA, the averages were.4 and.5 logmar in the and 29
Iranian Journal of Ophthalmology Volume 2 Number 4 29 groups, respectively (Table ). Other similar studies have demonstrated that there are no significant differences between these two types of IOLs. 6, According to our findings, the contrast sensitivity with and without glare was significantly lower in the group, and this is in agreement with findings of previous studies. 2,3,4,5 In the report by Vingolo et al, 3 the mean contrast sensitivity were 8.28 db and 9.8 db in the group and group by static program, respectively. The long-term performance of the AcrySof ReSTOR IOL after cataract surgery was assessed in the article by De Vries et al. 5 They reported that contrast sensitivity was relatively acceptable after their surgeries. Multifocal IOLs fall in the category of detractive lenses, and a lower contrast sensitivity could be due to defraction of light in higher spatial frequencies, and thus, light fails to focus correctly on the retina. This results in blurred vision and lower contrast sensitivity. We observed maximum differences between the two types of IOLs at higher spatial frequencies. One of the most important points in selecting the type of IOL for a given patient is their daily activities. For patients who spend most of their time doing work within a close distance from their eyes, IOLs can be a more appropriate choice. For those who are less involved with such types of work or who are dependent on distant vision, IOLs can be used to avoid the reduction in contrast sensitivity and associated complaints such as glare and halo experienced during driving, that is usually seen with IOLs. Some limitations of our study should be mentioned. We did not study or compare halo in the two groups. Some studies have examined this complication and report differences between them. 3, In most comparative studies of these two types of IOLs, or those investigating the performance of IOLs, patient satisfaction and quality of life was assessed. However, we failed to do so due to certain constraints. 3,6, Also, the intermediate vision was not assessed in our study. Conclusion Based on our findings, we can claim that there are no significant differences in the DVA of patients receiving IOLs as compared to ones. In terms of UNVA, IOLs can perform significantly better than IOLs. Also, a slight reduction in contrast sensitivity should be expected postoperatively when implanting IOLs. References. Bellucci R, Scialdone A, Buratto L, et al. Visual acuity and contrast sensitivity comparison between Tecnis and AcrySof SA6AT intraocular lenses: A multicenter randomized study. J Cataract Refract Surg 25;3(4):72-7. 2. Kohnen T, Allen D, Boureau C, et al. European multicenter study of the AcrySof ReSTOR apodized diffractive intraocular lens. Ophthalmology 26;3(4):584. 3. Vingolo EM, Grenga P, Iacobelli L, Grenga R. Visual acuity and contrast sensitivity: AcrySof ReSTOR apodized diffractive versus AcrySof SA6AT intraocular lenses. J Cataract Refract Surg 27;33(7):244-7. 4. Chiam PJ, Chan JH, Aggarwal RK, Kasaby S. ReSTOR intraocular lens implantation in cataract surgery: quality of vision. J Cataract Refract Surg 26;32(9):459-63. 5. Chiam PJ, Chan JH, Haider SI, et al. Functional vision with bilateral ReZoom and ReSTOR intraocular lenses 6 months after cataract surgery. J Cataract Refract Surg 27;33(2):257-6. 6. Cillino S, Casuccio A, Di Pace F, et al. One-year outcomes with new-generation intraocular lenses. Ophthalmology 28;5(9):58-6. 7. Blaylock JF, Si Z, Aitchison S, Prescott C. Visual function and change in quality of life after bilateral refractive lens exchange with the ReSTOR intraocular lens. J Refract Surg 28;24(3):265-73. 3
Hashemi et al AcrySof ReSTOR vs. AcrySof SA6AT 8. Ortiz D, Alió JL, Bernabéu G, Pongo V. Optical performance of and intraocular lenses in the human eye. J Cataract Refract Surg 28;34(5):755-62. 9. Souza CE, Muccioli C, Soriano ES, et al. Visual performance of AcrySof ReSTOR apodized diffractive IOL: a prospective comparative trial. Am J Ophthalmol 26;4(5):827-32.. Chiam PJ, Chan JH, Aggarwal RK, Kasaby S. ReSTOR intraocular lens implantation in cataract surgery: quality of vision. J Cataract Refract Surg 26;32(9):459-63.. Alfonso JF, Fernández-Vega L, Baamonde MB, Montés-Micó R. Prospective visual evaluation of apodized diffractive intraocular lenses. J Cataract Refract Surg 27;33(7):235-43. 2. Chiam PJ, Chan JH, Haider SI, et al. Functional vision with bilateral ReZoom and ReSTOR intraocular lenses 6 months after cataract surgery. J Cataract Refract Surg 27;33(2):257-6. 3. Alfonso JF, Fernández-Vega L, Señaris A, Montés-Micó R. Prospective study of the Acri.LISA bifocal intraocular lens. J Cataract Refract Surg 27;33():93-5. 4. de Vries NE, Franssen L, Webers CA, et al. Intraocular straylight after implantation of the AcrySof ReSTOR SA6D3 diffractive intraocular lens. J Cataract Refract Surg 28;34(6):957-62. 5. de Vries NE, Webers CA, Montés-Micó R, et al. Long-term follow-up of a apodized diffractive intraocular lens after cataract surgery. J Cataract Refract Surg 28;34(9):476-82. 3